001    /*
002     $Id: Expando.java 4578 2006-12-22 11:59:52Z blackdrag $
003    
004     Copyright 2003 (C) James Strachan and Bob Mcwhirter. All Rights Reserved.
005    
006     Redistribution and use of this software and associated documentation
007     ("Software"), with or without modification, are permitted provided
008     that the following conditions are met:
009    
010     1. Redistributions of source code must retain copyright
011        statements and notices.  Redistributions must also contain a
012        copy of this document.
013    
014     2. Redistributions in binary form must reproduce the
015        above copyright notice, this list of conditions and the
016        following disclaimer in the documentation and/or other
017        materials provided with the distribution.
018    
019     3. The name "groovy" must not be used to endorse or promote
020        products derived from this Software without prior written
021        permission of The Codehaus.  For written permission,
022        please contact info@codehaus.org.
023    
024     4. Products derived from this Software may not be called "groovy"
025        nor may "groovy" appear in their names without prior written
026        permission of The Codehaus. "groovy" is a registered
027        trademark of The Codehaus.
028    
029     5. Due credit should be given to The Codehaus -
030        http://groovy.codehaus.org/
031    
032     THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS
033     ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
034     NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
035     FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
036     THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
037     INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
038     (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
039     SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
040     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
041     STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
042     ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
043     OF THE POSSIBILITY OF SUCH DAMAGE.
044    
045     */
046    package groovy.util;
047    
048    import groovy.lang.Closure;
049    import groovy.lang.GroovyObjectSupport;
050    import groovy.lang.GroovyRuntimeException;
051    import groovy.lang.MetaExpandoProperty;
052    import groovy.lang.MissingPropertyException;
053    
054    import java.util.HashMap;
055    import java.util.Map;
056    import java.util.Map.Entry;
057    import java.util.List;
058    import java.util.ArrayList;
059    import java.util.Iterator;
060    
061    
062    /**
063     * Represents a dynamically expandable bean.
064     * 
065     * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
066     * @author Hein Meling
067     * @author Pilho Kim
068     * @version $Revision: 4578 $
069     */
070    public class Expando extends GroovyObjectSupport {
071    
072        private Map expandoProperties;
073    
074        public Expando() {
075        }
076    
077        public Expando(Map expandoProperties) {
078            this.expandoProperties = expandoProperties;
079        }
080    
081        /**
082         * @return the dynamically expanded properties
083         */
084        public Map getProperties() {
085            if (expandoProperties == null) {
086                expandoProperties = createMap();
087            }
088            return expandoProperties;
089        }
090    
091        public List getMetaPropertyValues() {
092            // run through all our current properties and create MetaProperty objects
093            List ret = new ArrayList();
094            Iterator itr = getProperties().entrySet().iterator();
095            while(itr.hasNext()) {
096                Entry entry = (Entry) itr.next();
097                ret.add(new MetaExpandoProperty(entry));
098            }
099                    
100            return ret;
101        }
102    
103        public Object getProperty(String property) {
104            // always use the expando properties first
105            Object result = getProperties().get(property);
106            if (result!=null) return result;
107            try {
108                return super.getProperty(property);
109            }
110            catch (MissingPropertyException e) {}
111            return null;
112        }
113    
114        public void setProperty(String property, Object newValue) {
115            // always use the expando properties
116            getProperties().put(property, newValue);
117        }
118    
119        public Object invokeMethod(String name, Object args) {
120            try {
121                return super.invokeMethod(name, args);
122            }
123            catch (GroovyRuntimeException e) {
124                // br should get a "native" property match first. getProperty includes such fall-back logic
125                Object value = this.getProperty(name);
126                if (value instanceof Closure) {
127                    Closure closure = (Closure) value;
128                    closure.setDelegate(this);
129                    return closure.call((Object[]) args);
130                }
131                else {
132                    throw e;
133                }
134            }
135            
136        }
137        
138        /**
139         * This allows toString to be overridden by a closure <i>field</i> method attached
140         * to the expando object.
141         * 
142         * @see java.lang.Object#toString()
143         */
144         public String toString() {
145            Object method = getProperties().get("toString");
146            if (method != null && method instanceof Closure) {
147                // invoke overridden toString closure method
148                Closure closure = (Closure) method;
149                closure.setDelegate(this);
150                return closure.call().toString();
151            } else {
152                return expandoProperties.toString();
153            }
154         }
155    
156        /**
157         * This allows equals to be overridden by a closure <i>field</i> method attached
158         * to the expando object.
159         *
160         * @see java.lang.Object#equals(java.lang.Object)
161         */
162        public boolean equals(Object obj) {
163            Object method = getProperties().get("equals");
164            if (method != null && method instanceof Closure) {
165                // invoke overridden equals closure method
166                Closure closure = (Closure) method;
167                closure.setDelegate(this);
168                Boolean ret = (Boolean) closure.call(obj);
169                return ret.booleanValue();
170            } else {
171                return super.equals(obj);
172            }
173        }
174    
175        /**
176         * This allows hashCode to be overridden by a closure <i>field</i> method attached
177         * to the expando object.
178         *
179         * @see java.lang.Object#hashCode()
180         */
181        public int hashCode() {
182            Object method = getProperties().get("hashCode");
183            if (method != null && method instanceof Closure) {
184                // invoke overridden hashCode closure method
185                Closure closure = (Closure) method;
186                closure.setDelegate(this);
187                Integer ret = (Integer) closure.call();
188                return ret.intValue();
189            } else {
190                return super.hashCode();
191            }
192        }
193    
194        /**
195         * Factory method to create a new Map used to store the expando properties map
196         * @return a newly created Map implementation
197         */
198        protected Map createMap() {
199            return new HashMap();
200        }
201    
202    }